From the Guidelines
Severe hypertension with blood pressure greater than 200 mmHg requires immediate intervention with intravenous antihypertensive medications, such as labetalol, to prevent end-organ damage. The management involves prompt administration of these medications in a monitored setting, typically an emergency department or intensive care unit. According to the most recent guidelines 1, in patients with severe hypertension, drug treatment with i.v. labetalol is recommended.
Key Considerations
- The goal is to reduce blood pressure by no more than 25% within the first hour, then to 160/100-110 mmHg within the next 2-6 hours, and then gradually to normal over 24-48 hours 1.
- Rapid, excessive drops in blood pressure can cause cerebral, cardiac, or renal hypoperfusion.
- After stabilization, transition to oral antihypertensives should be initiated, often with a combination of medications from different classes.
- Underlying causes such as pheochromocytoma, renal artery stenosis, or medication non-compliance should be investigated.
Treatment Options
- First-line medications include labetalol (initial dose 20 mg IV, followed by 20-80 mg every 10 minutes as needed) 1.
- Alternatively, hydralazine (10-20 mg IV) or enalaprilat (1.25-5 mg IV) may be used.
- Nicardipine (initial dose 5 mg/hr IV, titrated by 2.5 mg/hr every 5-15 minutes, maximum 15 mg/hr) is also an option 1.
Monitoring and Follow-up
- Patients require close follow-up after discharge to ensure blood pressure remains controlled.
- Regular monitoring of blood pressure, renal function, and cardiac function is essential to prevent complications and adjust treatment as needed 1.
From the FDA Drug Label
The time course of blood pressure decrease is dependent on the initial rate of infusion and the frequency of dosage adjustment. Nicardipine hydrochloride injection is administered by slow continuous infusion at a concentration of 0. 1 mg/mL. With constant infusion, blood pressure begins to fall within minutes. It reaches about 50% of its ultimate decrease in about 45 minutes For a gradual reduction in blood pressure, initiate therapy at a rate of 5 mg/hr. If desired blood pressure reduction is not achieved at this dose, increase the infusion rate by 2. 5 mg/hr every 15 minutes up to a maximum of 15 mg/hr, until desired blood pressure reduction is achieved.
The management for severe hypertension (blood pressure greater than 200 mmHg) involves administering nicardipine hydrochloride injection by slow continuous infusion.
- Initiate therapy at a rate of 5 mg/hr.
- Increase the infusion rate by 2.5 mg/hr every 15 minutes up to a maximum of 15 mg/hr, until desired blood pressure reduction is achieved.
- Monitor closely and adjust the infusion rate as needed to maintain the desired response 2.
- In patients with severe hypertension, higher infusion rates may produce therapeutic responses more rapidly, with an average maintenance dose of 8.0 mg/hr 2.
From the Research
Management of Severe Hypertension
Severe hypertension, defined as a blood pressure greater than 200 mmHg, requires immediate medical attention. The management of severe hypertension involves the use of parenteral drugs and careful monitoring of blood pressure.
Parenteral Drugs
Several parenteral drugs are available for the treatment of severe hypertension, including:
- Sodium nitroprusside: a potent vasodilator that can be used in patients with hypertensive emergencies, but should be used with caution in patients with impaired cerebral flow 3, 4
- Nicardipine: a calcium-channel blocker that can be used to treat severe hypertension, with a rapid onset of action and minimal side effects 3, 5
- Fenoldopam: a selective dopamine receptor agonist that can be used to treat severe hypertension, with the advantage of improving renal blood flow and causing natriuresis 4, 6
- Hydralazine: a vasodilator that can be used to treat severe hypertension, particularly in patients with eclampsia or preeclampsia 4, 6
- Esmolol: a beta-blocker that can be used to treat severe hypertension, particularly in patients with supraventricular tachyarrhythmias or myocardial ischemia 4
Oral Agents
Oral agents can be used to manage hypertensive urgencies, which are defined as a blood pressure greater than 120 mmHg without evidence of target-organ damage. Oral agents that can be used include:
- Nifedipine: a calcium-channel blocker that can be used to treat hypertensive urgencies, but should be used with caution due to the risk of rapid blood pressure lowering 4
- Captopril: an ACE inhibitor that can be used to treat hypertensive urgencies, but should be used with caution in patients with renal impairment or hyperkalemia 4
- Clonidine: an alpha-2 adrenergic agonist that can be used to treat hypertensive urgencies, but should be used with caution due to the risk of rebound hypertension 4
Clinical Diagnosis
The diagnosis of hypertensive emergencies depends on the clinical manifestations rather than the absolute level of blood pressure. The physician should be familiar with the pharmacological and clinical actions of drugs used to treat hypertensive emergencies, and should be able to render appropriate therapy based on the patient's clinical presentation 7, 6.